2023-05-10 16:36:53

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH] SUNRPC: Don't change task->tk_status after the call to rpc_exit_task

From: Trond Myklebust <[email protected]>

Some calls to rpc_exit_task() may deliberately change the value of
task->tk_status, for instance because it gets checked by the RPC call's
rpc_release() callback. That makes it wrong to reset the value to
task->tk_rpc_status.
In particular this causes a bug where the rpc_call_done() callback tries
to fail over a set of pNFS/flexfiles writes to a different IP address,
but the reset of task->tk_status causes nfs_commit_release_pages() to
immediately mark the file as having a fatal error.

Fixes: 39494194f93b ("SUNRPC: Fix races with rpc_killall_tasks()")
Cc: [email protected] # 6.1.x
Signed-off-by: Trond Myklebust <[email protected]>
---
net/sunrpc/sched.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)

diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c
index c8321de341ee..6debf4fd42d4 100644
--- a/net/sunrpc/sched.c
+++ b/net/sunrpc/sched.c
@@ -927,11 +927,10 @@ static void __rpc_execute(struct rpc_task *task)
*/
do_action = task->tk_action;
/* Tasks with an RPC error status should exit */
- if (do_action != rpc_exit_task &&
+ if (do_action && do_action != rpc_exit_task &&
(status = READ_ONCE(task->tk_rpc_status)) != 0) {
task->tk_status = status;
- if (do_action != NULL)
- do_action = rpc_exit_task;
+ do_action = rpc_exit_task;
}
/* Callbacks override all actions */
if (task->tk_callback) {
--
2.40.1